Lycianthes starbuckii E.Dean, Novon 4: 324, 1994

Dean, Ellen, Poore, Jennifer, Anguiano-Constante, Marco Antonio, Nee, Michael H., Kang, Hannah, Starbuck, Thomas, Rodrigues, Annamarie & Conner, Matthew, 2020, The genus Lycianthes (Solanaceae, Capsiceae) in Mexico and Guatemala, PhytoKeys 168, pp. 1-333 : 1

44 Lycianthes starbuckii E.Dean, Novon 4: 324, 1994 Fig. 100

Type.

México. México: Sierra de Nanchititla, oak forest across the reservoir from the town of Nanchititla, 1945 m, 8 September 1991, E. Dean 315 (holotype: UC [UC1862224]; isotypes: BM [001000924], DAV [DAV158254, DAV158084, DAV158083, DAV158082], ENCB, MEXU [MEXU01195795], MO [2246353], NY [00687930], XAL [XAL0106673, XAL0106672].

Description.

Perennial herb, from fusiform storage roots, usually prostrate to ascending, to 0.15 m tall, dying back each season. Indument of white, uniseriate, multicellular, simple, eglandular, spreading to appressed trichomes, 0.1-0.5 mm long. Stems greenish-purple, moderately to densely pubescent, usually compressed when dried in a plant press, with very little woody tissue; first stem 0.5-3 cm long to the first inflorescence, the internodes 2-5; first sympodial branching point usually dichasial, followed by a mixture of monochasial and dichasial branching, this branching extensive, usually resting on the soil surface. Leaves simple, those of the upper sympodia usually paired and unequal in size, the larger ones with blades 3-6 × 1.25-3 cm, the smaller ones with blades 1/4 to 1/2 the size of the larger, the leaf pairs similar in shape, the blades obovate, oblanceolate, ovate, broadly elliptic, or rhombic, thick chartaceous, sparsely to moderately pubescent, the primary veins 3-5 on either side of the midvein, the base cuneate, sometimes attenuate onto the petiole, sometimes oblique, the margin entire, usually irregularly undulate, the apex broadly acute to rounded, the petioles winged and poorly defined, to 1.8 cm long, sometimes absent. Flowers solitary, axillary, oriented horizontally; peduncles absent; pedicels 42-86 mm and erect in flower, 52-122 mm long, deflexed, and undulate in fruit, moderately pubescent with spreading trichomes of two distinct lengths, the shorter to 0.25 mm long and the longer to 0.5 mm long; calyx 3-4 mm long, 4-5.5 mm in diameter, narrowly to broadly conic, moderately pubescent, the margin truncate, with 10 linear appendages lying laxly near the corolla surface 2-6.5 mm long emerging ca. 0.5 mm below the calyx rim; fruiting calyx enlarged, 2-5.5 mm long, 6-12.5 mm in diameter, the appendages spreading to reflexed, often broken, 2-6.5 mm long; corolla 1-2 cm long (2.1-3.8 cm in diameter), rotate in orientation, mostly entire in outline (with shallow notches), with abundant interpetalar tissue, lilac, with violet stripes near the major veins adaxially, green and moderately pubescent near the major veins abaxially; stamens unequal, the filaments of three lengths, the two shortest filaments 1.25-3.25 mm long, the two medium filaments 1.5-3.75 mm long, the one long filament 2-5.25 mm long, the length of the long filament usually less than 2 times that of the medium filaments, glabrous, the anthers 3.25-5.25 mm, lanceolate to elliptic, free of one another, yellow, glabrous, poricidal at the tips, the pores round, dehiscing distally, not opening into longitudinal slits; pollen grains irregular in shape and number of pores; pistil with glabrous ovary, the style 7-10 mm, linear, straight to slightly curved, glabrous, the stigma round, shallowly lobed. Fruit a berry, separating from calyx at maturity and matures lying on the ground, 17-22 mm long, 7-17 mm in diameter, ovoid, the exocarp dull dark purple at maturity, glabrous, the mesocarp dark purple, soft and juicy, lacking sclerotic granules, the placental area light purple, powdery in texture. Seeds 2-29 per fruit, 3.5-4.5 × 3-4.3 mm, not compressed, depressed obovate, ridged and blistered along one side, black, the surface reticulum rough in texture with loose serpentine pattern and deep luminae.

Chromosome number.

2n = 24, Dean 315 ( Dean 2004)

Distribution and habitat.

Mexico, endemic to southwestern state of México, Sierra de Nanchititla, on level oak forest floor, 1945 m in elevation (Fig. 101 ).

Common names and uses.

Mexico. México: chilillo ( Dean 2004).

Phenology.

Flowering specimens have been collected July and August; specimens with mature fruits have been collected in October and November. The first author has observed in the field that the corollas open in the very early morning and close by late morning. The pollen of this species has a sweet fragrance.

Preliminary conservation status.

Lycianthes starbuckii is a rare species of central Mexico, represented by only four collections from the type location, which is not a protected area. The conservation status of L. starbuckii was investigated by Anguiano-Constante et al. (2018), and their preliminary conservation assessment for this species was Endangered.

Discussion.

Lycianthes starbuckii can be distinguished from other species of series Meizonodontae by its combination of prostrate to ascending habit, densely pubescent stems, thick-chartaceous leaves, lax calyx teeth at anthesis, moderately pubescent corolla lobes, and dark purple fruits with large brown to black seeds. Lycianthes starbuckii is unusual in the L. ciliolata complex in its habit and pubescent corolla lobes ( Dean 2004). In these characteristics, it is much closer to such species as L. moziniana and L. peduncularis . Lycianthes starbuckii may hybridize with L. rzedowskii , which grows in drainage areas near Nanchititla ( Dean 2004). There are specimens collected in southern Guerrero that strongly resemble L. starbuckii , but they have a more erect habit, rather than prostrate; these collections are discussed below under Difficult to Place Specimens. Field work is needed to investigate these populations.

Representative specimen examined.

Mexico. México: km 15 carretera El Estado-cañadas de Nanchititla, camino Torrecillas, 18.874, -100.3326, 1934 m, 27 Jul 2010, A. Rodríguez 6083 (IBUG, IEB, MEXU).

Figures

Figure 100. Image of isotype of L. starbuckii, Dean 315 (DAV). Image used with permission of the UC Davis Center for Plant Diversity.

Figure 101. Map of geographic distribution of L. starbuckii based on herbarium specimen data.